Research On Radar Target Angle Measurement Method Under Interference Conditions

As an important content in the field of radar signal processing,target angle estimation is the key technology for radar system to locate and track target.With the development of interference technology,the working environment of radar is more and more complex,and the problems in the estimation of target angle are also increasing.The target echoes received by the radar are always mixed with clutter and various interferences generated by the enemy,which seriously affect the performance of the radar system.Therefore,it is of great significance to study effective radar target angle measurement methods under the interference conditions,which are also the mainly works of this thesis.The thesis first introduces traditional sum differential beam single-pulse angle measurement methods such as double pointing method,half band method and direct weighting method,and analyzes the angle measurement performance of various algorithms through simulation experiments.Aiming at the angle measurement problem with sidelobe interference,this paper studies adaptive sum differential beam sidelobe canceller and receiver signal feature decomposition,and analyzes their performances and applicable conditions.The experimental results show that the two algorithms can achieve effective angle measurement under their respective applicable conditions.In addition,for the problems of adaptive filtering method in the mainlobe interference environment such as adaptive beam deformation and sidelobe level elevation,three adaptive single-pulse angle measurement algorithms: adaptive sum difference beam,constrained sum difference beam and least squares angle measurement curves fitting are studied.Among them,the adaptive sum difference beam algorithm directly uses the adaptive angle measurement curve to measure the angle.The experimental results show that the algorithm can maintain good performance when the interference angle deviates significantly from the target angle.The other two algorithms ensure that the adaptive angle measurement curve is not distorted and thus meets the required angle measurement accuracy.Aiming at the problem that the performance of traditional single-pulse angle measurement method is seriously degraded under the condition of main lobe(near main lobe)interference,a four-channel single-pulse angle measurement algorithm is studied.The angle measurement curve whose orthogonal dimension is undistorted when suppressing interference in a certain dimension is used for angle measurement in this algorithm.The simulation results show that the algorithm can achieve effective angle measurement of the plane array in the interference environment.Finally,according to the angle measurement problems encountered in the multi-path interference situation,an angle measurement algorithm in complex multipath interference environment is proposed in this thesis.In this algorithm,maximum signal angle measurement method and sum-difference beam anti-jamming algorithm are combined.The maximum signal method is used to determine the general angle of interference,if the angle is in mainlobe or near mainlobe,then a set of sum and difference beams are formed near the known beam direction for cancellation processing,the target angle will be estimated according to the processing results.This algorithm is proved to be effective in the multi-path interference situation by simulation experiment.